When you start resistance training it’s sensible to perform a relatively basic program. The number of repetitions and sets, as well as the exercise selection should remain stable. Then to progress you should incrementally increase the weight lifted. This increase in load will provide you immediate feedback that you’re making progress and getting stronger.
Over time, improvements in your strength levels will begin to plateau and there’ll be a greater need to vary your training. This variation can be provided by manipulating the repetitions, sets and weight lifted, which can make it a lot harder to keep track of whether you’re actually progressing.
For example, it’s difficult to understand whether back squatting 100kg for five repetitions is better than 105kg for three repetitions.
There are a few solutions to this issue.
We can perform some maximal strength testing (1 Repetition Max [RM] or 3RM) on a regular basis to assess strength gains. The downside to this is that it can be stressful and interrupt your training blocks.
We could also use velocity as a measure during training sessions and assume that if you move a similar or heavier load at a faster speed then they are making progress. However, measuring velocity during training (through linear position transducers and accelerometers) can be an expensive addition to your workout.
One simple way to monitor your strength progress is by using a formula to predict your 1RM from your heaviest set for that day.
There are a number of different formulas that have been proposed in research, with each formula having varying accuracy dependant on the:
- Exercise utilised
- Physiological properties of the individual and
- Number of repetitions used for the set
For the purpose of this article we will use the Epley formula.
RM = Repetition Max; w = Weight; r = Repetitions
By inputting the weight lifted and repetitions performed into the equation you can get an easy estimate of what your maximum strength will be on that day.
For the previous example where we wanted to assess the difference between five repetitions with 100kg and three repetitions with 105kg, here’s what you’d do:
As you can see, the 100kg back squat for five repetitions results in a slightly higher predicted 1RM than the 105kg for three repetitions. This can then be used to give feedback on your progress. By collecting data over time, you can start to build a good picture of your strength progression while still manipulating prescription variables.
Using this method is one way we track athlete progress at the NSW Institute of Sport. The below graph shows long term data from an NSWIS athlete.
The blue bars designate the load lifted in each session, while the orange line indicates the estimated 1RM for that day.
You can see that the general trend of the estimated 1RM increases over time while the blue bars constantly vary depending on the training prescription.
As with any estimation, there is a reasonable amount of error involved in the respective formulas.
Over and under prediction will often happen, especially when the number of repetitions performed are high (>5). This is something to be aware of and some periodic strength testing may be useful to check in on where you are exactly.
That said, this method provides a really nice monitoring tool, which can help provide feedback and guide your training process.
EPLEY, B. (1985) Poundage Chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises.